A vibration system of a loudspeaker comprises a diaphragm and a voice coil attached to one side of the diaphragm. The diaphragm of a loudspeaker in the prior art may have a single layer structure or a multilayer composite structure, and the acoustic performance thereof may be adjusted accordingly where necessary. A higher requirement for a loudspeaker leads to a higher requirement for the performance of the diaphragm thereof, thus, a diaphragm material that may meet the requirement for a high acoustic performance diaphragm is needed.
As an improvement, a polyether-ether-ketone composite material is widely used for the diaphragm in the prior art. Furthermore, a crystallized polyether-ether-ketone material is preferably used for the diaphragm so as to ensure the reliability of the loudspeaker. However, the crystallized polyether-ether-ketone material cannot sufficiently meet the requirement for a higher acoustic performance diaphragm, although it can ensure the reliability of the diaphragm. In addition, the resonance frequency f0 of the diaphragm made of the crystallized polyether-ether-ketone is too high to meet a technical requirement for a low resonance frequency f0. Therefore, it is necessary to improve the diaphragm with the traditional structure as described above, so that the improved diaphragm may satisfy the demands for high acoustic performance and low resonance frequency f0.